Rapid climatic fluctuations during the Guadalupian-Lopingian transition: Implications from weathering indices recorded in acid-insoluble residues of carbonate rocks, South China

Abstract

• The acid-insoluble residues of carbonate rocks preserve informations about terrestrial weathering. • Rapid changes of weathering indices imply climatic fluctuations during the GLB . • Two lower CIA corr units correspond to the P3 and P4 glaciations in Australia. • The high CIA corr interval around 260 Ma is related to the eruption of the ELIP . • Climatic fluctuations drive the co-evolution of continent-ocean-biodiversity system. The Guadalupian-Lopingian boundary (GLB) transition was regarded as a gradual warming period with the termination of the Late Paleozoic Ice Age (LPIA). However, the glacial-nonglacial cycles from Eastern Australia imply that the period was also influenced by climatic fluctuations. We here report on a GLB section of the South China Block confined by the conodont biostratigraphy to constrain weathering intensity and the associated climatic fluctuations during this critical interval. The chemical weathering indices were estimated by analyses of acid-insoluble residues extracted from carbonate rocks. Two weak weathering units (Unit 1 and 3, Early Capitanian and Early Wuchiapingian) and two strong weathering units (Unit 2 and 4, Late Capitanian and Middle Wuchiapingian) are identified. δ 13 C carb generally follow well the variation tracks of weathering indices. Two weak weathering units (Unit 1 and 3) correspond to the P3 glacial and the P4 glacial in high-latitude region of Australia. The CIA-converted land surface temperature and reported seawater temperature reflect the synchronous response of continental climate and marine conditions. The strong weathering duration (Unit 2) is closely related to the eruption of the Emeishan Large Igneous Province (ELIP) which promoted the temperature raising and induced the waning of high-latitude ice sheet accordingly. The climatic fluctuations paced with the onset, surge, and weakening of the ELIP should be responsible for the remarkable continent-ocean-biodiversity system changes and GLB extinction.